The husle of payment and registration, or worse, showing a 'random' company your otherwise disclosed financial status, to proof you don't have to pay them, yet again, ha!
To be honest, I think the future is in hosted services and recurring payments. No way to crack, unless you crack the server, and you pay little, each day, each month or each year, for as long as you are interested in that service. Note that a 'hosted service' can have a full blown desktop front-end..
From an implementation perspective it would require the management of payments (both from business & individuals) to be centralized @ the national level. (infact, for the system to work fully it would need to be internationally accepted)
This is exactly how student loans are organised in the UK - you have the payments deducted from your salary automatically (above a certain threshold).
For most people there is absolutely no paperwork & no complication, which is quite amazing for a government scheme!
I agree the rather insidious 'hosted services with recurring charges' will undoubtably become much more common in the near future as more people & devices become connected,
and while such a solution might reduce piracy, it doesn't make software accessible to all users irrespective of their wealth.
I think my proposal is abit too far off at the moment; it requires integration of national (and international!) systems that simply don't exist yet.
It would also require significant changes in the philosophy behind big business, as I imagine 'the greater good' would seem a rather alien concept to many big corporations.
I imagine many would be stuck in the mindset that 'We made this product, why should we give it to everyone, when some may never pay a penny for it?'.
Though you do see some promising signs that corporations are willing to compromise on profits to forward long-term goals such as industry expansion & advancement.
Open-Source being supported by big corporations is one very good example.
Providing tiered products (such as Windows 7ista) is another, as it atleast acknowledges the price point needs graduating - though graduating the feature set to achieve this is wasted effort that would be unnecessary in the licensing payment system I proposed.
The economics of software have never worked correctly in a Free market, simply because software goes from having zero supply (it hasn't been written yet), to infinite supply (replication is almost free).
This means the fundamental principle of supply & demand creating a price that is correct for the current market state doesn't work.
Perhaps in 50 years time, when world economics have been rewritten by the new world order - i'll be able to say 'told you so'

(now... if only I could patent this...

)